Safety device for electric-arc lamps



(No Model.) 3 Sheets-Sheet 1.

E. THOMSONQ SAFETY DEVIGE FOR ELECTRIC ARC LAMPS. N0.'289,580'. Patented Dec. 4, 1883.

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(No Model.) 3 Sheets-Sheet 2.

E. THOMSON.

SAFETY DEVICE FOR ELECTRIC ARC LAMPS. No. 289,580. Patented Dec. 4, 1883.

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(No Model.) 3 Sheets-Sheet 3.

E. THOMSON.

SAFETY DEVICE FOR ELEGTRIOARG LAMPS.

No. 289,580. Patented Dec. 4, 1883.

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M912. x; T fi /1 UNITED STATES PATENT ELIHU THOMSON, OF NEIV BRITAIN, ASSIGNOR TO THE THOMSOX-I-IOUTICN ELECTRIC COMPANY, OF CONNECTICUT.

SAFETY DEVICE FOR ELECTRIC-ARC LAMPS.

SPECIFICATION forming part of Letters Patent No. 289,580, dated December 4, 1883.

Application filed March 8,1853. (No mmlcl.)

To all whom, it may concern: rod. I ordinarily prefer to carry out my in- 50 Be it known that I, ELIHU THOMSON a citivention by connecting to the movable guides zen of the United States, and a resident of a rather stiff spring or springs, which tend to New Britain, in the county of Hartford and pull them downward or in a direction toward 5 State of Connecticut, have invented certain the arc, and in restraining said spring from new and useful Improvements in Safety Deactionbyadetentwhichengageswiththeguides 5 vices for Electric-Arc Lamps, of which the folor other parts connected with them, and is relowing is a specification. leased by any suitable device or devices when- My invention relates to electric-are lamps, ever the are becomes abnormally lengthened. IO and is designed to prevent permanent rupt- The guides and their connected parts might,

me of the general circuit upon which a series however, be made sut'ficiently heavy to act 60 of lamps are burning in case any one of said positively on the removal of the restraining lamps should fail to feed properly. :atch or detent. For controlling or releas- My invention provides a novel means for ing the detent, I ordinarily prefer to use a 15 bringing the carbons together and holding supplementalelectro-magnetorarmaturesuitthem in contact in case the lamp burns with ably arranged or connected to cause a release 6 5 an abnormally long are, or in case the are is of the detent upon an abnormal increase in extinguished from any cause. the length of are; but I do not limit my- My invention consists, first, in making the self in this respect, as the gist of my inven- 2o guides for the carbon-rod movable and protion consists in making the guides movable,

viding a means whereby said guides may be and in releasing them automatically by any 70 allowed to drop by their own weight, or may suitable means brought into action by an abbe drawn positively downward, as bya spring, normal increase in the length of are. It would in case of an abnormally long are. therefore be within my invention to employ 2 My invention consists, secondly, in forcing other electro-responsive devices instead of the regulating armature-lever, or the parts eleetromagnets, or to release the detent by 7 5 supporting the feed mechanism, to recede by the mechanical action of any portion of the some positivelyacting mechanism normally regulatonlever or mechanism when allowed held out of action, but brought into action by to recede sufficiently far by an abnormal in 0 an abnormal increase in the length of are, so crease in the arc length.

as to not only produce a complete release of In carrying out the third feature of my in So the carbon-rod, but also to prevent re-engage vention it is sufficient to produce a complete ment of the regulating mechanism. and continued release of the feed mechanism My invention consists, thirdly, in providing by any means, and I may therefore, in this 5 a means whereby all the parts of the lamp combination, employ a mechanism like a that are in contact with the carbonrod may spring, which is normally restrained or held be allowed to drop or recede upon an abnorout of action by a detent or catch until the mal increase in the length of are, so as to inproper time; or I may arrange for cutting out sure a complete movement of the carbon-rod the lifting electro-magnet at the same time 40 and a contact of the two carbons in case, that the guides are released.

through a defect of any portion of the feed I11 the accompanying drawings, Figure l is go mechanism, a sticking of the carbon-rod, or an elevation of an electric lamp embodying other defect, the carbon-rod should fail to one form otmyinvention, and showing the infeed properly. This portion of my invention vention applied to a clutch or clamp lamp 5 is ordinarily accomplished by combining the having one of the weltknown magnet systems two first features of my invention, since the employed for giving the requisite movement 95 feed mechanism and the guides are ordinarily to the carbon adjusting or feeding mechanism. the only parts which,under any circumstances, In this form of my invention the catch which could restrain the movement of the carbonprevents the carbon-guides from moving, is

controlled or released by the action of an electro-magnet, which I shall term a safety-magnet, and which magnet is here energized at the proper time by the closing of a contact connected to the lever of the regulating mechanism. Fig. 2 shows the safety devices of Fig. l separated from the other parts, and in the position occupied by them while the lamp .D and a portion of the clamp devices 0.

is operating properly. Fig. 8 shows the same devices after they have been released. Fig. 4 shows an equivalent arrangement of circuits and contacts for bringing the safety-magnet into operation. Figs. 5, (i, and7 show an improved device for conveying the currentto the carbon rod or carrier. 12 show other and modified arrangements of my invention.

In Fig. 1, D is a lifting or main-circuit magnet placed in the usual connection, embracing the carbons and the are at E E. Its circuit is indicated by the numeral 5, and passes from. the main wire at 2 through the coils of D to the guide-tube T, to the carbon-rod B, through the are at E E, and out at 3. S is the usual derived-circuit magnet, of high resistance, placed in the connection 6 around the are. G is 'acarbon-holding clamp or feed-controlling device, of any suitable constructionsuch, for instance, as is shown in my prior patent, No. 272,353, Figs. 2 and 3and R is the supporting-rod or carrier for the carbon E. Lis thelifting frame or lever actuated to raise and lower the clamp by the direct and derived circuit magnets D S, in the usual way. T is a frame or sleeve which carries the usual guides for the carbon-rod B, said guides being formed at the upper and lower ends of said sleeve or frame, as shown in Figs. 2 and 3. The frame or sleeve, and therefore the guides, is movable, and is itself guided in fixed openings in the general frame of the lamp H and in a supporting-arm, H, for the magnet The frame T and the guides for the carbon are free .to move vertically, either bytheir own weight or by the action of a spring; but are normally restrained from movement by means of a catch or detent A, which engages with a projection, B, on frame T, but may withdraw from engagement with said projection by the action of the safety-magnet M, with the armature or equivalent'portion of which said catch or detent is suitably connected. Vhen the frame or guides are released, a spring, F, or aweight pulls them down forcibly in any suitable wayas, for instance, th roughthe intervention of a piece, 1?, provided with aproj ection, as shown, for engagement with the frame T. The spring F also acts, through piece P and a projection, a, to pull the lever-L down forcibly and to hold 'it down, thus producing a complete disengagement of the carbon-feeding devices, and alsolowering the same, 'so that in'case any portion of said devices should stick toortendtahold the carbon-rod said ro'd' willnevertheless be lowered. The spring F Figs. 8, 9, 10, 1L andis sufficiently strong to also prevent re-engagement of the lifting or feeding devices under the action of the regulating-magnet system.

The magnet M is energized by the closing of contacts K, suitably connected with the feedregulating lever L, or equivalent portion of the feed-regulating mechanism, and suitably adjusted or placed to close a circuit, 9, e011- taining the magnet M and derived from the main circuit, whenever an abnormal or dangerous increase in the length of arc occurs and allows said lever to recede to an abnormal extent. When an abnormal arc and failure to feed occurs, the contacts at K being closed, the magnet M is energized, so that the frame T and guides for the carbon are pulled down, as also the lever L, and the upper carbon, owing to the release and lowering of all the parts that could tend to hold it up, is lowered into contact with the lower carbon, where it remains until the lamp is repaired or readjusted.

In Fig. 2 the parts are shown enlarged and in section in their normal or sustained position. The frame or tube T may be replaced by any mechanical equivalent, forming the sole guide for the carbon-rod B. At T is shown a convenient contact for maintaining good electrical connection with the rod B through the sleeve T, but is uncssential to its working. The same letters are used as in Fig. 1. v

In Fig. 3 the detent or catch A is shown withdrawn by the magnet M, and the parts have descended under the influence of their weight. but assisted by the force of the spring F, which, though desirable, is not essential if the parts are made of considerable weight. It is obviousthat the lug a might be connected to the tube or frame T instead of to the piece P. This arrangement is shown in Fig. 12,and would be a preferred arrangement if the spring were dispensed with and the weight of the parts depended upon.

In Fig. 4 is shown another arrangement of circuits, whereby the magnet M may be energized at the proper time. The magnet M is placed in a direct circuit, and is normally shunted by contacts at K until such contacts are opened by the lever L under the increased attraction of the derived-circuit magnet when the arc is abnormally lengthened. This arrangement is an obvious equivalent of that already described. The contact-spring T is shown in Figs. 5, 6, 7 as consisting of a comb, WV, of spring metal, Fig. 7, bent so as to lie around the carbon-rod, and each tooth formed in the arc of a circle. The comb thus bent is seated in a cavity or support at the lower end of T. This I find to be a very cheap contact device, even for use in a fixed position in a lamp to make connection with a carbon-rod. The comb \V is of thin hard-rolled copper, preferably.

In Fig. 8 a safety-magnet, M, is arranged to be normally in circuit, but to be cut out by contacts K upon the abnormal increase of a derived-circuit magnet, S, (with the armaturelever of which contacts I are connected,) forming, it may be, a portion of the ordinary regulating derived circuit in which the regulating derived-circuit magnet Sis placed. I11 this case the magnet M, byits attraction, holds the catch Ain engagement under normal working, and it is withdrawn by a spring, Z, on the cessation or decrease of magnetism in M, produced by the closing of the contacts at K when the arc increases abnormally,the retractor 17 being suitably adjusted for that purpose.

The spring Z may be dispensed with if a properinclination is given to the detentsurfaces to enable B to slide by or past A under its normal tendency to descend. The objection to the arrangement Fig. 8 is the necessity of providing for the maintenance of engagement of A and B until the current is put on, or manual operation or setting of the parts when the lamp is started. In Fig. 9 the sleeve Tis replaced by simple ring-guides T T for the rod B, said rings being united by a frame or rod held vertical by portions of the lamp ease, as H, but free to move when the catch A may be released by a magnet acting on it directly; or it may be released by the spring Z upon the removal or release of a second de tent, G, under the control of a derived-circuit magnet, S, or under the control of a magnet, M, thrown into action by the derived-circuit magnet, as in former figures. For the pur pose of depressing the regulating-lever simultaneously with the lowering of the guides, an electrical arrangement such as is shown in Fig. 9, whereby the lifting-magnet D is shortcircuited or cut out simultaneously with the lowering of the frame and guides T, may be employed. \Vhen thus short-circuited,the magnet loses its lifting-power and does not regain it until the parts are restored to their normal position, so that the lever L will be depressed by its own weight, combined with the action of the derived-circuit reg ulating-coil and will retain its position after the carbons come together. The demagnetization of the main-circuit coil is here shown as effected by ashort-circuiting of the same through contacts ma, one of which, in, is connected to T, and subserves the same function as the mechanically-actin g projection a, Fig. 12, and Figs. 1, 2, and 3. Other means might be employed for removing the current from the main-circuit magnet D at the same time that the arc abnormally lengthens and the guides are lowered, and other mechanisms might be employed in this connection for lowerin g the clutch or regulating mechanism, provided they be properly constructed and arranged to come into operation upon an abnormal increase in the length of arc, and to actsimultaneously with the lowering of the guides or other parts bearing upon or connected to the carbon-rod.

I11 Fig. 10 each bushing or guide for the carbon-rod R is provided with a separate catch, A, and is mounted so as to be movable in the lamp frame or case H H, and acted on by its depressing-spring. The magnet M, when actuated, causes the release of both bushings T T, either simultaneously or successively, as may be desired, according to the set of the catches A. The upper bushing, T, may have a flange, 1', which, when it is released, hold the regulating-lever L down.

Fig. 11 shows an arrangement whereby the supplemental safety magnet might be dispensed with and the mechanical action of the regulating-lever L or other portion of the regulating mechanism employed for releasing the catch and guides whenever such mechanism recedes abnormally under the influence of an abnormal flow of current in the derivedeircuit coil. G is the extra detent-l ever, which holds the catch A in engagement with B, and is arranged in the path of a projection, 15, from the lever L, so that when the lever is drawn down abnormally under the action of the derived-circuit regulating-coil the catch A will be removed.

Many other devices for dropping the guides at the proper time will readily suggest themselves to those skilled in the art, and I do not therefore limit myself in this respect, the gist of my invention consisting in making the guides for the carbon-rod movable and releasing said guides upon a failure of the carbon to feed properly, so as to insure a complete release of said carbon and a contact of the same with its opposite carbon, Nor do I limit myself as to the means for insuring a release and drop of the carbon-feeding mechanism simultaneously with the lowering or release of the guides, since the essence of my invention, so far as the third head thereof is concerned, consists, broadly, in autoinaticall y releasing or freeing all the portions of the lamp connected to or in contact with the rod upon an increase in the length of are due to a failure of the carbon to feed properly.

The details of mounting the guides so that they move at the proper time and the form of the detent or catch which holds them up may be varied indefinitely.

The safety-magn et which controls or releases the catch may be energized in any way, provided it be properly connected and arranged to release the catch at the proper time, as stated.

My invention may obviously be applied to any form of electric-arc lamp.

IVhat I claim as my invention is 1. In an electric lamp the guides for the carbon-carrier of which are made movable, the combination, with said guides, of detaining mechanism holding said guides stationary during normal feeding of the carbon, and means for releasing said guides upon failure of the carbon to feed properly. 7

2. The combination, with a carbon-carrier, of movable guides normally held stationary during the feed of the carrier, means for releasing said guides when an abnormal increase in the length of are occurs, and for simultaneously lowering with a positive movement the portion of the regulating mechanism which supports the feed-clutch or equivalent feed mechanism.

3. The combination, with the upper or movable carboncarrier in an electric lamp, of means for normally detaining or supporting those portions of the lamp outside of the feed devices that are in contact with said carboncarrier, and mechanism for releasing or withdrawing said supporting or detaining devices upon failure of the carbon carrier to feed properly.

4. In an electric lamp, the combination, with the movable and supporting portion for the feedregulating mechanism, of a supplemental retractor normally held out of action upon saidlever during feed of the carbon, and means for releasing said retractor upon failure of the carbon to feed properly.

5. The combination, with the carbon-carrier in an electric-arc lamp, of guides and feedregulating devices for said carrier, made movable, a detent or catch for normally holding the guides from movement, means adapted to act upon and lower the feed-regulating devices, also normally held out of action by a catch or detent, a releasing or safety electromagnet for releasing said catches, and means for rendering said magnet operative upon an abnormal increase in the length of are.

(3. The combination, with the lever L, which supports or actuates the feed-regulatin g mechanism, of a supplemental spring normally held out of action by a catch or detent, and means for releasing said catch or detent upon an ab normal increase in the length of are.

7. The combination, with the lever which supports or actuates the feed-regulatin g mechanism, of a supplemental spring normally held out of engagement with the said lever by a catch or detent, a releasing or controlling electro-magnet for said catch, and means for bring ing said magnet into or out of action upon failure of the carbon to feed properly.

8. The combination, in an electric-are lamp, of a frame supporting movable guides for the carboncarrier, a spring for acting on said frame so as to pull it downward. or toward the are, a catch normally engaging with the frame, and means for releasing the catch upon an abnormal increase in the length of are.

9. The combination, in an eleetriearc lamp the guides for the carbon-carrier of which are made movable, of a spring for acting on said guides so as to pull them toward the are, a catch or detent normally holding said guides from movement, and a controlling electromagnet for said catch, which releases said guides upon an abnormal increase in the length of are.

10. The combination, with the guides, of the frame T, carrying the same, a spring, F, an engaging-plate, P, for engaging with the frame and with the lever L, and a detent for holding the frame and the spring out of action.

11.- The combination, with the frame T, of a detent normally holding the same from movement, a spring which tends to pull the frame downward, and a lug or projection operated by the spring for engaging with the lever of the regulating mechanism when the frame is released.

12. The combination of frame T, carrying the guides for the carbon-carrier, a catch, A, and a lug or projection, a, moving simultaneously with the frame for producing a receding movement of the regulator-lever L simultaneously with the release and movement of the guides.

13. The combination, with the carbon-car rier, of a contactspring formed from a comb, TV, the continuous band of which is bent in a circle around the carrier, while its teeth entirely surround said carrier and are bent on a line parallel with the carrier, substantially as shown and described, so that the curved portion of the teeth rest against the surface of the same.

Signed at Boston, in the county of Suffolk and State of Massachusetts, this 6th day of March, A. l). 188;.

ELIHU THOMSON.

lVitnessesz' JosnPH J. SKINNER, HARRY B. Roemzs. 

